public final void  accept(ASTVisitor visitor) {        if (visitor == null) {            throw new IllegalArgumentException();        }        // begin with the generic pre-visit        if (visitor.preVisit2(this)) {            // dynamic dispatch to internal method for type-specific visit/endVisit            accept0(visitor);        }        // end with the generic post-visit        visitor.postVisit(this);    }

abstract void accept0( visitor);

 

void accept0(ASTVisitor visitor) {        boolean visitChildren = visitor.visit(this);        if (visitChildren) {            // visit children in normal left to right reading order            acceptChild(visitor, getException());            acceptChild(visitor, getBody());        }        visitor.endVisit(this);    }

 

final void  acceptChild(ASTVisitor visitor, ASTNode child) {        if (child == null) {            return;        }        child.accept(visitor);    }